Cecil Moore wrote:
Roy Lewallen wrote:
Using that nearly-universal definition, the speed of an EM wave in any
other medium is VF * c where VF is the "velocity factor".

If I remember correctly, at Texas A&M we used an
equation like:

c' = VF(c)

Writing c-prime like that told us that it wasn't
the speed of light in free space.
my recollection from optics is

c/c' = n, index of refraction for the c' medium, (c always used as the
constant in a vacuum).